Orientation reference system for medical imaging

ABSTRACT

The present invention relates to positioning a medical imaging system in relation to an object. In order to provide improved positioning possibilities which facilitate the workflow during an intervention, a medical imaging apparatus (10) is provided with an image acquisition arrangement (12), which is positionable in relation to an object (16) to acquire image data (18) of the object from different directions. An output unit (14) is arranged to provide the image data. According to the invention, first movement direction indicators (22) are provided to indicate possible movement directions of the image acquisition arrangement in relation to the object. Further, a display apparatus (24), comprising a display area (26) to display image data (30) of an object provided by an image acquisition arrangement and a movement direction indication (28), may be provided, wherein the movement direction indication is configured to provide second movement direction indicators (32) in relation to the displayed image data of the object to indicate possible movement directions of the image acquisition arrangement in relation to the object. The first movement direction indicators and the second movement direction indicators are equivalent.

CROSS-REFERENCE TO PRIOR APPLICATIONS

This application is a continuation of application Ser. No. 14/116,151,filed Nov. 7, 2013, which is the U.S. National Phase application under35 U.S.C. § 371 of International Application No. PCT/IB2012/052259,filed on May 7, 2012, which claims the benefit of European PatentApplication No. 11166065.0, filed on May 13, 2011. These applicationsare hereby incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to positioning a medical imaging system inrelation to an object. In particular, the present invention relates to amedical imaging apparatus, a display apparatus for displaying medicalimage data of an object, an imaging system, and a method for positioninga medical imaging system.

BACKGROUND OF THE INVENTION

Medical imaging is commonly performed, for example, during operationalprocedures, such as in a hospital. To acquire image data of an objectunder investigation or examination from different directions, an imageacquisition device can be moved in relation to the object. To provide asurgeon, for example, with image information about the currentsituation, for example during an interventional procedure, images areprovided, for example, on a display. In case the surgeon requires imagedata from a different region of interest, or from a different direction,the image acquisition device and the object, for example a patient, aremoved in relation to each other such that further images can be acquiredfrom a different position. Usually, this is performed by an imageacquisition operator. Thus, a respective instruction has to becommunicated to the operator. However, instructions by the surgeon maybe misleading, for example an instruction like “move upwards”, which mayrefer to the displayed image as well as to the image acquisition deviceitself. Thus, it has been shown that after a further image acquisitionstep, still further adjustment instructions concerning the position ofthe image acquisition device in relation to the patient are quite oftennecessary. An imaging system is described in WO 2008/120121 A1, whereinan adjustment of the table in relation to the imaging unit is providedto maintain the region of interest within the image region of theimaging unit in response to a rotation of the imaging unit about an axisof rotation, to assure that the region of interest is within the imagearea of after rotating the imaging unit.

SUMMARY OF THE INVENTION

There is a need to provide improved positioning possibilities whichfacilitate the workflow during an intervention.

The object of the present invention is solved by the subject-matter ofthe independent claims, wherein further embodiments are incorporated inthe dependent claims.

It should be noted that the following described aspects of the inventionapply also for the medical imaging apparatus, the display apparatus, theimaging system, and the method for positioning a medical image system.

According to a first aspect of the invention, a medical imagingapparatus is provided, comprising an image acquisition arrangement, andan output unit. The image acquisition arrangement is positionable inrelation to an object to acquire image data of the object from differentdirections. For the positioning, the image acquisition arrangement ismovable in relation to the object in at least two movement directions.The output unit is arranged to provide the image data. First movementdirection indicators are provided to indicate possible movementdirections of the image acquisition arrangement in relation to theobject.

In relation with the present invention, the term “direction” refers tomovement possibilities, which movements comprise translations androtations, i.e. translational and rotational movements, as well ascombinations thereof. Thus, the term “movement direction indicator”refers to movement possibilities and can thus be understood as “movementpossibilities indicator”.

For example, the image acquisition arrangement is movable in relation tothe object by translational movement. As another example, the imageacquisition arrangement is movable in relation to the object byrotational movement. Still further, the image acquisition arrangement ismovable in a combination of rotation and translation.

The rotational movement, the translational movement as well as thecombinations thereof, can be provided in a plane as one- ortwo-dimensional movement. The rotational movement, the translationalmovement as well as the combinations thereof, can also be provided inspace as three-dimensional movement.

According to an exemplary embodiment of the invention, the imageacquisition arrangement is an X-ray imaging device with an X-ray sourceand an X-ray detector.

According to a further exemplary embodiment, the first movementdirection indicators are provided on the image acquisition arrangementsuch that they are visible to the user.

According to a further exemplary embodiment, the first movementdirection indicators are provided next to a control interface foraccomplishing the positioning.

According to a further exemplary embodiment, the first movementdirection indicators are provided such that a bijective identificationof the complementary direction is possible.

According to a second aspect of the invention, a display apparatus fordisplaying medical image data of an object is provided, comprising adisplay area and a movement direction indication. The display area isconfigured to display image data of an object provided by an imageacquisition arrangement. The movement direction indication is configuredto provide second movement direction indicators in relation to thedisplayed image data of the object to indicate possible movementdirections of the image acquisition arrangement in relation to theobject.

According to a further exemplary embodiment, the movement directionindication is configured to be updated after a positioning movement.

According to a third aspect of the invention, an imaging system isprovided, comprising a medical imaging apparatus according to one of theabove described aspects and embodiments, and a display apparatusaccording to one of the above described aspects and embodiments. Theoutput unit is configured to provide the image data to the displayapparatus. The movement direction indication on the display apparatusrelates to the movement possibilities of the image acquisitionarrangement. The first movement direction indicators and the secondmovement direction indicators are equivalent.

According to a further exemplary embodiment, the first and the secondmovement direction indicators are of the same type.

According to a fourth aspect of the invention, a method for positioninga medical image system is provided, comprising the following steps: a)providing first movement direction indicators indicating possiblemovement directions of an image acquisition arrangement in relation toan object; b) displaying image data of the object, and providing secondmovement direction indicators in relation to a displayed image data ofthe object, which second movement direction indicators indicate thedifferent movement directions of the image acquisition arrangement;wherein the first and the second movement direction indicators areequivalent; c) identifying at least one of the second movement directionindicators for an intended movement of the image acquisitionarrangement; and d) accomplishing the intended movement of the imageacquisition arrangement in relation to the object on behalf of at leastone of the first movement direction indicators which is equivalent tothe identified second movement direction indicator.

According to an aspect of the invention, for example, in case of anoperational intervention, the surgeon is provided with directionindicators that can be used for instructing the required movements incase of a desired (re-) positioning or (re-) adjustment of the imageacquisition device. Since, for the performance of the positioning oradjustment of the image acquisition device, equivalent directionindicators are provided, for example to the operator responsible foraccomplishing the positioning procedure, it is possible to give clearand direct instructions which cannot be misinterpreted, but which ratherresult in a precise positioning for further image acquisition steps.According to an aspect of the invention, an orientation reference systemis thus provided, which is presented on the one hand to the (first) uservia providing movement direction indicators on the display, and on theother hand presented to a staff member (as second user) responsible foraccomplishing the actual movement of the image acquisition device orarrangement, in form of further movement direction indicators, both ofwhich indicator groups are equivalent to each other, thus forming anorientation reference system according to the invention. The inventiveorientation reference system provides improved positioning possibilitiesfacilitating the workflow during an intervention. In particular, in caseof X-ray imaging, the orientation reference system saves unneeded, andthus unwanted, X-ray radiation procedures, thereby reducing the overallamount of radiation to which the patient is exposed to, due to theimproved positioning and alignment commands provided by the equivalentmovement direction indicators.

These and other aspects of the present invention will become apparentfrom and elucidated with reference to the embodiments describedhereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention will be described in thefollowing with reference to the following drawings.

FIG. 1 illustrates a medical imaging apparatus according to an exemplaryembodiment of the invention;

FIG. 2 illustrates a display apparatus according to an exemplaryembodiment of the invention;

FIG. 3 illustrates an imaging system according to an exemplaryembodiment of the invention;

FIG. 4 illustrates a further exemplary embodiment of a medical imagingapparatus;

FIG. 5 shows a further exemplary embodiment of a medical imagingapparatus;

FIGS. 6A to 6E illustrate examples of movement direction indicators;

FIG. 7 illustrates basic steps of a method according to an exemplaryembodiment of the invention; and

FIGS. 8A to 8C illustrate further aspects of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 shows a medical imaging apparatus 10 with an image acquisitionarrangement 12 and an output unit 14. The image acquisition arrangement12 is positionable in relation to an object 16 to acquire image data 18of the object 16 from different directions. For example, the object 16is a patient. For the positioning, the image acquisition arrangement 12is movable in relation to the object in at least two movementdirections, which is indicated by a double arrow 20. The output unit 14is arranged to provide the image data 18.

According to the invention, first movement direction indicators 22 areprovided to indicate possible movement directions of the imageacquisition arrangement in relation to the object.

According to a further exemplary embodiment, although not further shownin FIG. 1 , for the movement of the image acquisition arrangement inrelation to the object, the image acquisition arrangement is movable.

The image acquisition arrangement may be movable by a direct interactionof the user or an operator, for example by manual actuation of thepositioning. The movement can also be accomplished with the aid ofmechanical movement devices or actuators, such as electro-magnetic orpneumatic driving devices.

The relative movement of the image acquisition arrangement in relationto the object can also be accomplished by a movement of the objectitself, for example, with a moveable object support device, such as amovable patient table.

The relative movement can also be accomplished by both moving the imageacquisition arrangement and the object itself.

According to the present invention, the first movement directionindicators, which will be discussed in more detail below, allow anidentification of the different movement directions, and thus allow toaddress, as well as to perform, a movement of the image acquisitionarrangement in relation to the object for the image acquisition of theobject from different directions or different positions.

FIG. 2 shows a display apparatus 24 for displaying medical image data ofan object. The display apparatus 24 comprises a display area 26 and amovement direction indication 28. The display area 26 is configured todisplay image data 30 of an object, for example a patient, provided byan image acquisition arrangement.

The term “image data” refers to directly detected image data as well asto processed image data. For example, image as detected is shown on thedisplay. The detected information may also be transformed by imageprocessing steps, such as digital subtraction steps, e.g. based onpreviously acquired image data. The detected information may also betransformed or processed into further image information such as agenerated model, a segmented structure or the like.

The movement direction indication 28 is configured to provide secondmovement direction indicators 32 in relation to the displayed image dataof the object to indicate possible movement directions of the imageacquisition arrangement in relation to the object. For example, foursecond movement direction indicators 32 are shown. Of course, othernumbers of the first and second movement direction indicators are alsopossible.

For example, the movement direction indication is configured to providethe second movement direction indicators 32 according to the correlationof the orientation of the displayed image to the orientation of adetector of the image acquisition arrangement.

According to a further aspect of the invention, the second movementdirection indicators on the display apparatus correlate with themovement directions of the image acquisition arrangement in correlationwith the image plane of the displayed image.

The first movement direction indicators 22 and the second movementdirection indicators 32 will also be explained in the following.

FIG. 3 shows an imaging system 34 with a medical imaging apparatus 10and a display apparatus 24, which have already been described in basicaspects above.

As an example for a medical imaging apparatus 10, the image acquisitionarrangement 12 is an X-ray imaging device 36 with an X-ray source 38 andan X-ray detector 40. For example, the X-ray imaging system device 36may be a C-arm device, as shown for exemplary purposes in FIG. 3 . TheC-arm device as shown, for example, may comprise a C-arm structure 42,to which both ends the detector 40 and the X-ray source 38 are mounted.The C-arm structure 42 is movably mounted to a support 44, in which theC-arm is slideably mounted. The support 44 also allows rotationalmovement around a horizontal axis 46. The support 44 is mounted to asuspended arm structure 48 with an L-shape, shown only for exemplarypurposes. The L-arm structure 48 is mounted to a support 50, which ismounted to the ceiling of the operational theatre and allows ahorizontal movement along support rails 52 as well as a rotationalmovement around a vertical axis 54.

The C-arm device is provided such that an object 56 can be locatedbetween the detector 40 and the X-ray source 38, in a way that, due tothe different moving possibilities of the C-arm, image acquisition ofthe object 56 is possible from a number of different directions, whichare not further shown.

The object 56 is arranged on a support device, for example a patienttable 58, allowing horizontal and vertical adjustment for furtherpositioning and adjustment purposes. Therefore, the table 58 issupported by a respective adaptable stand 60.

The display apparatus 24 is provided in the vicinity of the patienttable, for example by being mounted to a ceiling support 62, whichallows position adjustment of the display apparatus 24, according to theuser's needs.

Further, adaptable lighting 64 is indicated, as well as an input orcontrol interface 66 for adjusting peripheral equipment, such as thelighting 64 or the table 58.

Further, a control arrangement 68 is shown in the foreground, whichcomprises a plurality of display devices 70, as well as a plurality ofinput devices, for example a keyboard 72, a mouse 74, a graphic tablet76, as well as an input device 78 with a joystick 80.

The control interface 78 may be provided for accomplishing a positioningof the medical imaging apparatus, for example the C-arm device. Forexample, the movement of the C-arm may be actuated and controlled by thejoystick, with which positioning commands can be entered to control themedical imaging apparatus.

The first movement direction indicators 22 are provided on the imageacquisition arrangement such that they are visible to the user. Forexample, the first movement direction indicators are arranged on visiblehousing parts, such as the housing of the detector, or support parts ofthe image acquisition arrangement, wherein the housing or support partsare moving in accordance with the position movement. As an example,reference numerals 82 indicate first movement direction indicators 22provided on the surrounding faces of the housing of the detector 40.Thus, the first movement direction indicators 22 identify possiblemovement directions of the image acquisition arrangement.

The first movement direction indicators may be referred to as anorientation system of the image acquisition arrangement.

According to a further exemplary embodiment of the invention, the firstmovement direction indicators 22, 82 are provided as adaptable movementdirection indicators 84, as is also shown in relation with FIG. 8 . Forexample, the first movement direction indicators may be provided as oneor more display units with adjustable display content. This allows, forexample, adjusting the displayed content, i.e. the adjustment of thefirst movement direction indicators according to different needs andindividual situations.

In case the first movement direction indicators are adapted or changed,the second movement direction indicators may be adapted or changedaccordingly.

Of course, theoretically, the first and second movement directionindicators could be different, but this would mean the necessity of adecoding or translation step on the side of at least one of the users,which could then lead to unwanted misunderstanding.

For example, the adaptable first movement direction indicators 84 may beprovided as bi-stable displays. These displays only need electric supplyfor their activation and change of the display content, respectively.That is, once they have been adjusted to show or display the desiredinformation, the electric supply can be disconnected.

As already mentioned in relation with FIG. 2 , the display apparatus 24comprises the display area 26 to display the image data 30 of the object56, which image data 30 is provided by the image acquisition arrangement10.

For example, the second movement direction indicators 32 are shown inthe edge zone of the display area 26, for example, overlaid to thedisplayed image data 30.

As an aspect of the invention, the first movement direction indicators22 and the second movement direction indicators 32 are equivalent.

The term “equivalent” refers to the first and second movement directionindicators being synonymic, or being in a predetermined reference toeach other, or being comparable. Thus, the term “equivalent” refers tothe first and the second movement direction indicators as beingcorresponding to each other.

According to an exemplary embodiment of the invention (not furthershown), the first and the second movement direction indicators are ofthe same type.

According to an exemplary embodiment of the invention (not furthershown), the first and the second movement direction indicators can havedifferent members, but with the same sort or type of symbols and thesame logic.

By providing the medical imaging apparatus and the display apparatuswith a common orientation reference system in form of the first andsecond movement direction indicators, it is possible that a surgeon, forexample, studying the displayed image of the object, for example of apatient, finds movement direction indicators next to the image such thathe or she can identify a desired movement direction of the imageacquisition arrangement in relation to the object for furtheracquisition steps. Thus, for determining the further necessary movementof the apparatus in relation with the patient, these directions cancorrectly be addressed, which means relieve with respect to the user'stime and attention needed to identify the movement direction.

Once the surgeon has identified the desired movement direction, therepositioning or adjustment of the position of the image acquisitionapparatus can easily be accomplished by a staff member responsible foroperating the device, for example a technician. For example, in case ofa direct manual actuation of the positioning, i.e. by direct interactionwith the C-arm itself, the technical operator finds the equivalentmovement direction indicator on the housing of the detector, forexample, such that he or she directly knows in which direction the imageacquisition arrangement has to be moved for further acquisition steps.

Showing the orientation information on the device and on the display isalso helpful for the surgeon to move the C-arm in the right directionhimself.

By providing the first movement direction indicators next to the controlinterface 78, for example next to the joystick 80, as indicated withsmall dots 86, it is also possible to enter a respective control commandby the joystick 78 by simply receiving the respective movement commandin form of the second movement direction indicator, and to look for theequivalent first movement direction indicator next to the joystick 78.

Of course, the first movement direction indicators 22 could also beprovided on the monitor or displays 70, the graphic tablet 76, or alsoin relation with the mouse 74 or the keyboard 72.

The first and second movement direction indicators will further beexplained in relation with FIGS. 6A to 6E.

Before explaining the movement direction indicators, it is referred toFIG. 4 , showing an ultrasound device 85 as a further example for animage acquisition arrangement. The ultrasound device 85 has a movabletransducer unit 87 to be moved along an object 90, for example apatient, wherein the first movement direction indicators are provided onthe outside of the transducer unit 87 as indicated with referencenumeral 92. As further shown, the ultrasound device 85 may be connectedto a processing unit 94, for example by a wire connection, which couldalso be provided as a wireless connection. Further, a display 98 can beconnected to the processing unit 94, as schematically indicated with aconnection line 100. The display 96 provides the second movementdirection indicators 32, for example in the surrounding of a displayedultrasound image 102. Of course, the second movement directionindicators 32 could also be provided as overlay to the ultrasound image102. This allows to identify a movement direction by looking at theultrasound image 102 and then to identify the necessary movement of the,for example, handheld movable transducer unit 87 by looking for theequivalent of the first movement direction indicators 92. It is alsopossible to have one person conducting the movement of the transducerunit 87, and another person studying the ultrasound image 102, toidentify the necessary movements which will then be conducted by thefirst person.

FIG. 5 shows a further example of an image acquisition arrangement inform of a steerable catheter device 104 with a handheld control device106 to move and steer a catheter 108 inside an object structure 110, forexample inside a patient's vessel structure or other tubular structure.First movement direction indicators, indicated with reference numeral112, are provided on the outside of the control device 106 next to thecontrol or regulation mechanism. The steerable catheter device mayprovide image data to a processing unit 114, connected to the catheterdevice by a wire connection or wireless connection 116, which processingunit 114 is further connected to a display 118 by a further connection120. Second movement direction indicators 32 may be provided next to animage 122. Thus, the movement directions for next image acquisitions maybe identified by looking at the display 118, which movement directionscan then be identified on behalf of the equivalent first movementdirection indicators 112 as provided on the handheld control device 106.

According to a further example (not shown), a stiff endoscope isprovided, which, for example, can be used in arthroscopy or laparoscopy,in which similar first movement direction indicators are provided, aswell as second movement direction indicators. The orientation, given bythe movement direction indicators, facilitates, for example, theorientation for the user to move the endoscope in the desired direction.

According to an aspect of the present invention, the movement directionindicators are provided such that a bijective identification of thecomplementary direction is possible. In the context of the presentinvention, the complementary direction is the opposite direction, i.e.the same line in a plan or in space, but with an opposite orientation.This, and also the following passages, may apply for the first and/orthe second movement direction indicators.

For example, the coding of the movement direction indicators is providedsuch that in case of partly hidden movement direction indicators, thenon-visible movement direction indicators can be identified. Forexample, in such case where a surgeon is standing on one side of animage acquisition arrangement, being able to see only a part of theprovided movement direction indicators, and an operator responsible forthe positioning of the imaging apparatus is standing on the other side,where the part visible for the surgeon is not visible, but the parthidden for the surgeon is visible, both users can identify therespective movement direction indicator as seen from the other user.

According to a further aspect of the invention, the movement directionindicators are provided as denominated symbols such that the movementdirections are addressable with unambiguous messages. The messages maybe used in a communicatively way. For example, the messages may be termssuch as spoken words, for example commands. The messages may also begestures conducted by the surgeon. For example, the terms are commonwords to be called by both user identifying desired or intended movementdirection and an operator initiating the movement, for example toconfirm the respective movement command.

According to the present invention, the movement direction indicatorsrelate to different movement directions such that opposing directionsare indicated with different denominated symbols, clearly allowing anidentification of the respective movement direction.

According to a further exemplary embodiment of the invention, themovement direction indicators are provided for a movement plane, whereinthe movement direction indicators are provided as a planar orientationcoding 150, as will be described with reference to FIGS. 6A to 6D.

FIG. 6A shows a medical image, for example an X-ray image 152, in which,as second movement direction indicators, a surrounding chromatic circle154 is shown with four different colours 154 a, 154 b, 154 c, and 154 d.For example, the four colours are arranged such that the respectiveopposite colour is provided as a complementary colour.

FIG. 6B shows the second movement direction indicators as dotted coding156 with a first dot symbol 156 a, a second dot symbol 156 b, a thirddot symbol 156 c, and a fourth dot symbol 156 d. The dot symbols areprovided such that respective opposite symbols show the sum 7 in total.Thus, by only being able to see one part of the symbols, the respectiveopposite symbols can be identified.

FIG. 6C shows a cardinal direction system 158 with a letter “N” as firstcardinal direction indicator 158 a, an “E” as second cardinal direction158 b, an “S” as third cardinal direction 158 c, and a “W” as fourthcardinal direction 158 d.

FIG. 6D shows clock positions 160 with the clock numbers “3”, “6”, “9”,and “12” arranged around the X-ray image 152.

The movement direction indicators may also be provided relating totwo-dimensional Cartesian coordinate system.

According to a further exemplary embodiment of the invention, the second(and first) movement direction indicators relate to a spatial movementin relation to an image plane, wherein the movement direction indicatorsare provided as a spatial orientation coding 162.

According to a further example, numerical indicators 164 of a virtualdice are shown wherein the dice has n faces. The numerical indicatorsare arranged such that the sum of opposing numerical indicators is n+1.As indicated in FIG. 6E, four numerical indicators 164 a to 164 d arearranged around the X-ray image 152. A fifth numerical indicator 164 eand a sixth numerical indicator 164 f are provided in combination with athree axis graph 166 indicating the plane of the image with a horizontalaxis 168 and a vertical axis 170, and the direction in the depth of theimage plane with a further third axis 172. The direction from the imageplane towards the user, i.e. in the opposite direction than the depthdirection 172, a still further arrow 174 is shown in a dotted manner.Thus, all directions of a dice with six faces are provided, wherein therespective opposing faces sum up to the number of seven to provide thepossibility to identify the respective complementary direction.

The terms “up”, “down”, “right”, “left”, “depth” etc. relate to theimage plane, and thus the detector plane and not to an actual position.

According to a further example, although not further shown, the spatialmovement can also result in spatial orientation coding in form of aspherical colour model. For example, complementary colours are orientedon opposing sides of the spherical colour model.

The first and second movement direction indicators may be providedrelating to a three-dimensional Cartesian coordinate system. Themovement direction indicators may further be provided relating to acylindrical or spherical coordinate system. The movement directionindicators may also be referred to as orientation symbols.

It is explicitly noted that the above described aspects in relation withthe second movement direction indicators shown in the context of thedisplayed image, also apply for the first movement direction indicatorsas well. In particular, the first and second movement directionindicators are provided such that a bijective identification of thecomplementary direction is possible. The first and the second movementdirection indicators thus correlate with the movement direction of theimage acquisition apparatus.

As indicated above, according to an exemplary embodiment of theinvention (not further shown), the display area may be configured toprovide the second movement direction indicators in combination with theimage data. For example, the second movement direction indicators may beprovided superimposed at the edge areas of the display area. The displayarrangement may also comprise an orientation area at the edge or outsideof the display area in order to provide the movement directionindicators. Of course, the provision of an edge area outside of adisplay arrangement can also be provided in combination with overlaidindicators to an actually displayed image.

In the following, basic steps of a method 200 shall be explained withreference to FIG. 7 . In a provision step 210, first movement directionindicators 212 indicating possible movement directions of an imageacquisition arrangement in relation to an object are provided. In afurther step, a displaying sub-step 214 is provided in which image data216 of the object is displayed. In a further provision sub-step 218,second movement direction indicators 220 are provided in relation to thedisplayed image data of the object, which second movement directionindicators indicate the different movement directions of the imageacquisition arrangement. The displaying sub-step 214 and the provisionsub-step 218 may also be provided as two parallel steps, which is alsoindicated with a dotted separation line 221.

According to the present invention, the first and the second movementdirection indicators 212, 220 are equivalent to each other, which isindicated by a wave-like line with double arrows 222.

In an identification step 224, at least one of the second movementdirection indicators 220 for an intended movement of the imageacquisition arrangement is identified. Further, in an accomplishmentstep 226, the intended movement of the image acquisition arrangement inrelation to the object is accomplished on behalf of at least one of thefirst movement direction indicators which is equivalent to theidentified second movement direction indicator. Thus, the secondmovement direction indicator identified in the identification step 224is so-to-speak transferred to the first movement direction indicators212 to identify the respective equivalent, which is indicated by adotted arrow 227.

The first provision step 220 may also be referred to as step a), thedisplaying and provision sub-steps 214, 218 may also be referred to asstep b), the identification step 224 as step c), and the accomplishmentstep 226 as step d).

According to a further exemplary embodiment, the movement directionindication is configured to be updated after a positioning movement.

According to an example, not further shown, a movement of the medicalimaging apparatus in relation with the object is detected and therespective information is provided to the display, where the secondmovement direction indicators are updated such that the actual positionof the imaging apparatus in relation with the object is presented inform of the position of the second movement direction indicators inrelation to the image of the object. For example, a C-arm is rotated inrelation to the object for x degrees for positioning. Thus, a secondindicator, on the display, showing a certain movement possibility of theC-arm is rotated respectively in relation to the image of the object onthe display; i.e. in case the image is kept unchanged, the secondindicator is rotated also for x degrees.

According to a further example, also not shown, a movement of themedical imaging apparatus in relation with the object is detected andthe respective information is provided to the display. Further, a newimage is acquired and the image data is provided on the display. Thesecond movement direction indicators are updated such that the actualposition of the imaging apparatus in relation with the object ispresented in form of the position of the second movement directionindicators in relation to the (new) image of the object.

According to a further example, also not shown, a movement of the imagein relation to the display can also be reflected in an update of thesecond movement direction indicators. For example, an image is rotatedfor 90 degrees for better understanding, leaving the C-arm at itsposition. The second movement direction indicators are also rotated,together with the image, for 90 degrees.

The update may be provided after a positioning movement and a furtherimage data acquisition. For example, after the accomplishment step 226,a further image acquisition step 228 is provided to acquire image datawhich can then be used for updating the image data in the displayingstep 214. This is indicated with an arrow 230 from the further imageacquisition frame 228 to the frame 214. However, it must be noted thatthe update feature is not a necessary feature of the method as describedin relation with FIG. 7 , which is indicated with a line separationsymbol 232, indicating that the update is a possible add-on but not anessential feature. Once the image data is updated, also the secondmovement direction indicators are updated in relation to the displayedimage data of the object.

For example, in case of a movement of the image due to a further imageacquisition of the positioning, the second movement direction indicatorsare arranged, e.g. positioned or amended in their content shown to theuser, according to the movement of the image acquisition apparatusitself. For example, in case of a rotation or mirroring of the imageacquisition arrangement, the second movement direction indicators arealso rotated or mirrored to match with the new image.

The image acquisition arrangement may be configured to acquire imagedata in a projection or image plane, and the second movement directionindicators relate to movement in relation to the projection plane, forexample, with the projection plane and/or relating to the depth of theprojection plane

Before referring to FIGS. 8A to 8C, some further aspects are describedin the following.

In case of an interventional C-arm procedure, X-ray images may be takenfrom any direction. The C-arm can be moved from a projection position tothe projection position by a C-arm operator under instruction of a user,for example a surgeon. The communication between the user of a C-armoperator is facilitated with the present invention by providing the userand the C-arm operator with the same and consistent orientationinformation related to the last acquired X-ray image as well as theorientation information being visible on the C-arm itself. Thus,position adjustments can be clearly defined by both user and C-armoperator, thus improving the general understanding of the C-armorientation and also the communication between the user and the C-armoperator. Consequently, the time needed, or consumed so-to-speak, forthe X-ray image acquisition, can thus be significantly reduced. Asanother advantage of the present invention, it must be noted that theinvention also allows the reduction, or nearly elimination, ofsuperfluous use of X-ray, since unnecessary X-ray image acquisitions areprevented.

In particular, in case the C-arm is operated from a lateral positionwith respect to the patient anatomy, which most of the times results ina necessary rotational adjustment of the X-ray images on the X-raymonitor to ensure usual interpretation of the projected anatomy by theuser in an upright orientation (head-up), or also possible mirroring ofthe displayed image, the clear definition in which direction to move theC-arm in order to achieve a desired projection, is facilitated accordingto the present invention, thus improving the overall workflow during aC-arm interventional procedure.

In particular, aspects such as the rotation and/or mirroring of theimage on the X-ray monitor, the hindered sight of the C-arm operator tothe operation field during position adjustment, the small visible areaof the operation field, for example in case the patient is completelycovered with sterile drapes, and in particular also instructions of thesurgeon to move the C-arm in a certain direction that can be misleading,as an instruction like “move upwards” may refer to the displayed X-rayimage as well as to the C-arm itself, which can represent differentadjustment directions, are greatly relieved by the present invention bythe provision of a common orientation reference system for the imageacquisition arrangement itself and in relation with the displayed imagepresented to the surgeon.

According to the present invention, the visible clarification of theX-ray image orientation on the X-ray monitor and the accordingdirections on the C-arm itself, or the respective input or controldevice like a joystick, saves time and reduces the amount ofsuperfluously acquired X-ray images.

The present invention is feasible, for example, for mobile C-arms inparticular, which are operated from the back of the system for positionadjustments, which hinders the view to the operation field for the C-armoperator and therefore especially lack of visible orientationinformation on the C-arm in relation to the acquired mostly rotatedX-ray projections on the X-ray monitor. Thus, according to the presentinvention, misunderstandings between user and C-arm operator areprevented, as well as the correct position adjustment of the C-arm isensured.

According to a further aspect of the present invention, it is alsoprovided to present orientation symbols, or in other words firstmovement direction indicators, on several locations on a C-arm, forexample, to ensure that at least a part of one of the respective sets ofsymbols is visible to the user. In case the detector shows the firstmovement direction indicators, it is also possible to provide a sterilecoverage with clear drapes to ensure the visibility of the system duringsurgical or interventional procedures.

Of course, it is possible to provide different types and differentnumbers of first and second movement direction indicators. For example,in case flat detectors with a rectangular shape are used, and thushaving four visible sidewalls of a housing, these can be equipped with arespective number of symbols marking the respective directions. In caseof cylindrical image intensifiers, also three, or four, five, etc., ofthe first and second movement direction indicators could be provided. Ofcourse, in case the system is equipped with a reduced number of movementpossibilities, the movement direction indicators are adapted accordinglyin their numbers and also in their content with respect to the bijectivedecoding aspect.

As shown in FIG. 8A, an X-ray image 180 showing a spinal structure 182in horizontal manner is shown on a display 184. The X-ray image 180 isprovided by a C-arm device which is only partly shown in FIGS. 8A to 8C.However, a detector 186 is shown which is provided with first movementdirection indicators 188, showing “12 h” and “3 h”, thus relating toclock positions as described in relation with FIG. 6D.

Next to the X-ray image 180, respective second movement directionindicators 190 are provided, which second movement direction indicatorsare provided such that the respective movement direction in relation tothe image content shown in the X-ray image 180 has the same correlationas the respective movement indicator on the detector with respect to theobject, for example the patient, under investigation. In other words,the detector having the “12 o'clock” symbol 12 h on the side facingtowards the head of the patient, as indicated with reference numeral192, is also presented next to the spinal structure indicating the samedirection.

As shown in FIG. 8B, for a better understanding of the image contentshown, the X-ray image 180 is usually rotated such that the respectivedirection “12 o'clock” of the spinal structure is arranged so-to-speakwith the head-up of the patient. If the surgeon is now studying theimage content and wishes to have an X-ray image from an area of thespinal structure closer to the neck, i.e. in relation with a patient tomove the image a bit more upwards, he or she can simply give a commandto have an X-ray image from a position after a movement in the “12o'clock” direction. The C-arch operator can then move the C-arch in arespective direction by simply manually moving the X-ray apparatus in arespective direction, which is the direction visible to a personstanding on the opposite side of the surgeon in case of FIGS. 8A to 8C,or to enter a respective command, as described before.

In case the surgeon wishes to have an X-ray image from a positionfurther down the spinal structure, he or she simply has to say “move to6 o'clock”. Despite the 6 o'clock symbol not being visible to a personstanding on the other side, due to the bijective identification, theoperator for moving the C-arch knows that the 6 o'clock is opposite tothe 12 o'clock, thus facilitating the interaction as required.

Similar is the case, for example, if the surgeon wishes to receiveinformation on the side of the image indicated with the 9 o'clockinformation. He or she can then give the movement direction “more to 9o'clock” in order to make the C-arm operator move the C-arm respectivelyand to acquire a further image as shown in FIG. 8C, in which the spinalstructure, here indicated with reference numeral 194, a bit more to theright side with reference to the display area.

It has to be noted that embodiments of the invention are described withreference to different subject matters. In particular, some embodimentsare described with reference to method type claims whereas otherembodiments are described with reference to the device type claims.However, a person skilled in the art will gather from the above and thefollowing description that, unless otherwise notified, in addition toany combination of features belonging to one type of subject matter alsoany combination between features relating to different subject mattersis considered to be disclosed with this application. However, allfeatures can be combined providing synergetic effects that are more thanthe simple summation of the features.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, such illustration and descriptionare to be considered illustrative or exemplary and not restrictive. Theinvention is not limited to the disclosed embodiments. Other variationsto the disclosed embodiments can be understood and effected by thoseskilled in the art in practicing a claimed invention, from a study ofthe drawings, the disclosure, and the dependent claims.

In the claims, the word “comprising” does not exclude other elements orsteps, and the indefinite article “a” or “an” does not exclude aplurality. A single processor or other unit may fulfill the functions ofseveral items re-cited in the claims. The mere fact that certainmeasures are re-cited in mutually different dependent claims does notindicate that a combination of these measures cannot be used toadvantage. Any reference signs in the claims should not be construed aslimiting the scope.

The invention claimed is:
 1. A medical imaging apparatus comprising: anX-ray imaging device including an X-ray source and an X-ray detector,wherein the X-ray detector comprises a housing that has four sidewalls,the X-ray imaging device positionable in relation to an imaged object inat least two movement directions and configured to acquire image data ofthe imaged object from the at least two movement directions; a displaydevice configured to display on a display screen: a diagnostic image ofthe imaged object, based on the image data from the X-ray imagingdevice, and second movement direction indicators in relation to thediagnostic image, wherein the second movement direction indicators arepositioned on the display screen to indicate orientation of the X-raydetector in relation to orientation of the displayed diagnostic image;and first movement direction indicators configured to indicate possiblemovement directions of the X-ray imaging device in relation to theimaged object, wherein the first movement direction indicators areprovided on the X-ray imaging device with a movement direction indicatorof the first movement direction indicators provided on each of the foursidewalls of the housing of the X-ray detector, wherein the firstmovement direction indicators correspond to the second movementdirection indicators, thereby forming a common orientation referencesystem for positioning the X-ray imaging device in relation to theimaged object, wherein the first movement direction indicators areconfigured to indicate spatial movement in relation to an image plane,and wherein the first movement direction indicators include-numeralindicators of “3”, “6”, “9”, and “12” that are positioned on the foursidewalls of the housing of the X-ray detector in a clock arrangement.2. The medical imaging apparatus according to claim 1, wherein the firstmovement direction indicators are configured as adaptable movementdirection indicators.
 3. The medical imaging apparatus according toclaim 1, wherein the first movement direction indicators are configuredsuch that complementary directions indicated by the first movementdirection indicators and second movement direction indicators arebijectively related.
 4. The medical imaging apparatus according to claim1, wherein the first movement direction indicators are configured asdenominated symbols such that the movement directions are addressablewith unambiguous messages.
 5. The medical imaging apparatus according toclaim 1, wherein the display device is disposed at a first site which isadapted for a surgeon to perform an interventional procedure; and thefirst movement direction indicators are disposed at a second site, whichis adapted for an image acquisition operator to position the x-rayimaging device in relation to the image object; and the second sitebeing different from the first site; and wherein the display device isconfigured to display the second movement direction indicators to thesurgeon and further including another display device at the second siteconfigured to display the second movement direction indicators to theimage acquisition operator.
 6. The medical imaging apparatus accordingto claim 1, wherein the first movement direction indicators are disposedon the housing out of a radiation path between the X-ray source and theX-ray detector.
 7. The medical imaging apparatus according to claim 1,wherein movement direction indicators corresponding to the firstmovement direction indicators on the X-ray imaging device are providednext to a control interface configured to control positioning of themedical imaging apparatus.
 8. A medical imaging apparatus comprising: apatient support; an imaging gantry configured to move relative to thepatient support, the imaging gantry carrying a diagnostic imagingapparatus configured to generate image data of an imaged object, whereinthe diagnostic imaging apparatus includes an X-ray source and an X-raydetector comprising a housing that has four sidewalls; first movementdirection indicators configured to indicate each of a plurality ofmovement directions in which the diagnostic imaging apparatus ismovable, wherein the first movement direction indicators are provided onthe diagnostic imaging apparatus with a movement direction indicator ofthe first movement direction indicators provided on each of the foursidewalls of the housing of the X-ray detector; and a display deviceconfigured to receive the image data and display on a display screen adiagnostic image, based on the image data from the imaging gantry, andsecond movement direction indicators in relation to the displayeddiagnostic image, the second movement direction indicators configured toindicate the plurality of movement directions indicated by the firstmovement direction indicators, wherein the second movement directionindicators are positioned on the display screen to indicate orientationof the X-ray detector in relation to orientation of the displayeddiagnostic image, and wherein the first movement direction indicatorsinclude numbers “3”, “6”, “9”, and “12” that are positioned on the foursidewalls of the housing of the X-ray detector in a clock arrangement.9. The medical imaging apparatus according to claim 8, furtherincluding: a user interface configured to control movement of thediagnostic imaging apparatus; and third movement direction indicatorsconfigured to indicate each of the same plurality of movement directionsas the first movement direction indicators and the second movementdirection indicators.
 10. The medical imaging apparatus according toclaim 9, wherein the display device is disposed at a first siteconfigured for a surgeon to perform an interventional procedure, thedisplay device being disposed such that the diagnostic image data andthe second movement direction indicators are visible to the surgeon; andthe user interface and the third motion direction indicators aredisposed at a second site from which movement of the imaging gantryrelative to the patient support is controlled such that the third motiondirection indicators are visible to an image acquisition operator. 11.The medical imaging apparatus according to claim 8, wherein the secondmovement direction indicators include a chromatic circle.
 12. Themedical imaging apparatus according to claim 8, further including: acatheter; a handheld control device configured to move and steer thecatheter; catheter movement direction indicators disposed on an outsideof the handheld control device to indicate each of a plurality ofmovement directions in which the catheter is movable, the secondmovement direction indicators being indicative of the same movementdirections as the catheter movement direction indicators.
 13. Themedical imaging apparatus according to claim 8, wherein the displaydevice is further configured to display indicators indicative of depthrelative to a plane defined by the plurality of motion indicators. 14.The medical imaging apparatus according to claim 8, wherein the firstmovement direction indicators are disposed on the housing out of aradiation path between the X-ray source and the X-ray detector.
 15. Themedical imaging apparatus according to claim 8, wherein movementdirection indicators corresponding to the first movement directionindicators on the X-ray imaging device are provided next to a controlinterface configured to control positioning of the diagnostic imagingapparatus.